M230212a
© BY J&I BLOCK" above "GERMANY".
J. & I. Block was no producer but merely importer/distributor and the figural drinking sets they sold are very similar to those produced by the factory of Rudolph Heinz from the town of Neuhaus am Rennweg (Thuringia). One thing that struck me while checking my archive on unidentified marks was that the name J. & I. Block perfectly matches the "I-J-B" mark included as M130601; it could well be that both marks were used by the same company.
M230212a
© BY J&I BLOCK" above "GERMANY".
M230212b
© BY J&I BLOCK" without country of origin indicator.